Soale



Jan. 19 1932. I HALLWOOD 1,841,948

SCALE Filed Dec. 20, 1928 gmnntov IJEZZZWM weighing scale of the t e disclosed, for example, 1n my aforesaid pending application Serial No. 283,620. The casing is formed to provide a drum chamber 2, in which is rotatably mounted a weight indicatingand value computing drum 3. This drum, as usual, is of light weight construction so as to be capable of revolving freely in response to applied weight loads, and has its peripheral surface formed with weight and value computing indicia 4. The casing is formed to include an opening 5 arrangedin registration with the normal zero position of the drum 3, and this opening is rovided with a lens structure 6 comprising t e present invention.

The lens structure is formed to comprise a pair of glass lens sections which when united produce a com osite lens of planoconvex ormation. A lens of this type rovides for magnification of the indicla va ues found on the drum 3 and facilitates the reading of the drum. Between the lens'structure and the drum there is provided a stationarily supported reading line in the form'of a taut- 1yl held, small diameterwire. The ends of t is wire are attached to arms 8 which are adjustably supported in connection with the base of the scale. Normally, this wire, which is indicated by the humeral 9, extends longitudinally of the lens structure in the plane of the meeting surfaces 10 of the .lens sections 7, and in registration with the normal or zero position of the drum 3.

In ordinary scale construction the reading lens is of integral form and the observed re lationship between the wire 9 and the indicia bearing surface of the drum depends upon the position of the scale reader with respect to the lens. Unless the observer looks through the center of the lens the values are apt to be misread. The present invention, t erefore, provides positive means for compelling the scale reader to assume a desired or proper position when reading the scale indicator.

This result .is attained, in the preferred form of the invention, by renderin the surfaces10 of the lens sections opaque y grinding said surfaces during the rocess of man ufacturing the lenses. I pre er to grind the surfaces 10 rather than to interpose between them an opaque strip of material, such as is disclosed in my Patent No. 1,729,106, for the reason that the ground surfaces do not reflect the light rays engaging the same as is done when an opaque strip is used. Such reflection is highly undesirable in that the scale reader may be mislead in properly understanding the drum values. With the ground surfaces, however, this difiiculty is completely avoided. Moreover, the ground surfaces when viewed in true edge elevation present nothing more than a very line which does not inter ere with the vision of the obangle of the-observer in looking t and computing drum,

a stationary character and values presented upon the movable drum 3. v

If, however, the scale reader should not view the surfaces 10 from a desired or proper reading position, the said surfaces will present what appears to be a strip or ribbon of some considerable thickness, dependin upon the lirough the lens. Therefore, due to the opaquenessof the surfaces 10 the observer is compelled to change his position to a proper one before reading the scale in order that true values may be ascertained. Most scale manufacturers use elaborate recautions in the manufacture of their pro nets to secure a high degree of accuracy. A large part ofthis accuracy has been sacrificed by careless reading of the weight values presented to the observer by the scale drum or indicator. It will be observed that the present invention provides a lens structure designed for the urpose ofreducin or minimizing error A om this source, an provides generall for increased accuracy in the operation 0 computing scales.

What is claimed is:

1. .In a scale, a rotatably mounted weight indicating and computing drum, a casmg around said drum having a lens opening, a lens positioned in said opening and oompris ing a pair of adjoining sections formedto include plano and opaque meeting surfaces, said surfaces extendin' longitudinally of the lens in substantially 't e center thereof, and astationary reading wire positioned between said lens and said drum and situated in the 1 plane of the meeting surfaces of the lens sections. Y

2. a scale, a rotatable weight indicating and computing drum, a casing around said drum provided with a lens opening, a lens structure adaptedto occupy said opening and formed to include a pair 'of separable sections, the meeting surfaces of said sections being ground, and a reading wire arranged between said drum and said ens and stationary substantially in the plane of the ground meeting surfaces of said lens.

3. In a scale, a rotatable weight indicating a stationary casing arranged adjacent to said drum and provided with a lens openin a plano-convex lens stationarily positions in said opening, said lens consisting of a pair of duplicate sections having ground meeting surfaces, and a longitudinally extending reading element positioned between the circumference of said drum and .the inner surface of said lens and arranged III v memes substentiaiiy in the plane of the grcitmd meeting surfaces of the lens sections.

4. In a scale, a. retatabie weight infiicating emi computing drum, a stationary easin er ranged Eadie-semi; to said drum and provided with e lens egening, a lens structure edete to occupy sei opening and formed to im; uzie e psir of separable sections, at least one of the meetin, surfaces of said sections being m groun sn e readin wire erranged between said drum end said ens and stationery substantiaiiy in the plane of the ground meeting; surfaces 0f said iens.

ii. In a sesie, a rotatable mounted weight w indicating emi com uting drum, e casing ermine seiei epening eving a lens opening, a lens positioned in said opening and comprising a pair 0f edieiriing sections formed to include a pair of meeting surfaces, at least one 20 of said surfaces being opaque, and e readin wire arranged between said drum and sai iens and; stationary substantially in the plane of the meeting surfaces of said lens.

In testimony whereof I afiix my si nature. 35 NATHAN A. HALLW OD. 

